Carburetor idle valve heater



NOV- 2, 1965 D. L. WHITMORE ETAL 3,215,417

CARBURETOR IDLE VALVE HEATER Filed Jan. 2, 1963 2 Sheets-Sheet l Dona/d L. Whitmore George C. VanGa/der INVENTORS BY I@ NOV- v2 19.65 A D. L. wHlTMoRE ETAL 3,215,417

CARBURETR IDLE VALVE HEATER Filed Jan. 2, 1963 2 Sheets-Sheet 2 F/ge 24 \\v\\\\\\\\\ 50 \\\y\ \\\\(l\\\l:\

l f se 50 34 52 40 39 52 George 6I Van Galder l N VEN TOR S.

ni/muy HMM,

United States Patent O 3,215,417 CARBURETOR IDLE VALVE HEATER Donald L. Whitmore and George C. Van Galder, Central Point, Oreg., assignors to V & W Manufacturing Co., Inc., Central Point, Greg., a corporation of Gregori Filed Jan. 2, 1963, Ser. No. 249,561 6 Claims. (Cl. 261-142) The present invention generally relates to a heating device combined with the idling metering valve employed in a carburetor of an internal combustion engine and this application is a continuation-impart of application Serial No. 89,864 tiled February 16, 1961 for Jet Heating Device, now abandoned.

It is a primary object of the present invention to provide a heating device used in conjunction with a metering valve which meters the fuel which passes through the idling orifice of the carburetor. By heating the liquid fuel that passes through the idling orifice, this heated fuel will be accelerated into the main volume of fuel passing through the carburetor which causes the main body of fuel to be vaporized but still does not increase to any appreciable degree the temperature of the main volume -of lfuel passing through the carburetor. By heating only a -small portion of the fuel that is discharged into the carburetor, there is no adverse affect on the volumetric efficiency of the engine thereby eliminating power loss which occurs from conventional methods of heating carburetors which normally employ devices which heat the entire fuel source or heat the body of the carburetor in some manner. In actual practice, it has been found that heating all of the fuel going into a carburetor or heating the entire carburetor body lsuch as in the venturi results in considerable power loss and a reduction in the power output of an engine at a constant throttle setting. The present invention completely eliminates such power loss by heating only a minor portion of the fuel passing into the main fuel body and this is accomplished by heating a portion ofthe fuel which passes through the idling ori-tice.

Another very important object of the present invention is to reduce considerably oil dilution which normally occurs when starting a cold engine by heating a small portion of the fuel that meters through the idling orice of the carburetor. This reduction in oil dilution is accomplished by the fuel being vaporized with the heating device rather than there being an overich liquid going into the combustion chamber which dilutes the engine lubricating oil in a manner well known.

Still another very important object of the present iuvention is to improve the starting characteristics of an engine by preheating the heating device Ibefore starting so that the engine will immediately start without choking and a smooth idling engine will beimmediately obtained.

Still another feature of the present invention is to provide a volume control idle screw having a heating device incorporated therein with the entire structure being integrally interconnected in such ra manner to provide a positive electrical and mechanical connection. The builtin volume control idle screw provides for a positive electrical snap-on connection of the electrical terminal lead. The advantage of this type connection provides easy adjustment and installation and reduces excessive heat transfer to the terminal point connection and also reduces excessive oxidation of the electrical connection.

A further advantage of the present invention is to pro- 3,215,417 Patented Nov. 2, 1965 "ice provides for proper heat transfer without the use of external insulation.

Under certain conditions a carburetor will ice up as a result of humidity and temperature conditions of the ambient atmosphere especially during the time the carburetor of an internal combustion engine is being utilized to supply an air fuel mixture to an idling engine. When the humidity and temperature conditions are at a critical point, the venturi effect caused by the carburetor will greatly reduce the temperature of the Iair entering the carburetor and cause the excess water content of the air to condense and to form ice on certain portions of the carburetor exposed to the flow of air therethrough. This icing condition produces r-ough idling and can also cause the internal combustion engine to stall. In addition, when yan internal'combustion engine is cold the choke or similar device must be used in order to reduce the amount of air passing through the carburetor. This reduced amount of air results in an overrich fuel mixture and a subsequent loss in power. Still further, the liquid fuel used in a majority of the internal combustion engines now in use does not readily vaporize when it is extremely cold.

The main object of this invention is to provide an idle valve heating device which may be utilized to preheat the fluid being metered thereby in order that the operation of the carburetor with which the idle valve is associated may operate more eihciently. By heating an idling metering valve utilized to control the fuel intake through certain passages `during the idling of an internal combustion engine, the fuel being metered by the valve will be 4accelerated into the main fuel path resulting in more complete vaporization of the fuel and smoother operation of the internal combustion engine. Further, by heating a valve utilized to meter liquid fuel, the liquid fuel is preheated and is also more readily vaporized in this manner.

A further object of this invention, in accordance with the immediately preceding object, is to provide an idling valve heating device constructed in a manner whereby Iit may be readily secured to various types` of idling metering screws which have portions thereof exposed.

A still further object of this invention is to provide an idling valve heating device which will be capable of being installed on various types of conventional carburetors with little or no modifications being necessary to the carburetors themselves.

A final object to be specifically enumerated herein is to provide an idling valve heating device which will con-`v form t-o conventional forms of manufacture, be of simple construction and be easy to operate .so as to provide a device that will be economically feasible, long lasting and relatively trouble free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a fragmentary side elevational View of a portion of the intake manifold of an internal combustion engine having a carburetor mounted thereon and the carburetor idle valve heater of the present invention incorporated therein with parts of the carburetor and manifold being broken away to illustrate the orientation of the valve heater and also illustrate the manner vof heating a porti-on of the fuel passing through the idling orice past the heated metering screw;

FIGURE 2 is a longitudinal sectional View of the carburetor idle valve heater;

FIGURE 3 is an exploded group perspective view of the components of the idling valve heater;

FIGURE 4 is a fragmental sectional view illustrating a slightly modified form of the present invention;

FIGURE 5 is a detailed sectional View of another form of the invention;

FIGURE 6 is a fragmentary side elevational view of a portion of the intake manifold of an internal combustion engine having a carburetor mounted thereon and a modified form of the heater removably secured to the vidling metering screw of the carburetor with portions of 'mounting flange 112 of an intake manifold generally referred to by numeral 114. The construction of the carburetor 110 is conventional and includes a ow passage 116 for a fuel and air mixture. The present invention has to do with the idling orifice 118 which communicates with the passage 116 and includes a passage 128 extending to a source of fuel supply such as the fioat bowl or the like of the conventional carburetor. A threaded bore 122 extends to the exterior of the carburetor and the threaded bore terminates at the juncture between the orifice 118y and the passage 120 and threadedly receives a metering screw 124 having a tapered needle 126 on the inner end thereof for ladjustment in relation to the orifice 118 whereby rotation of the screw 124 will move the needlel 'valve 126 towards or away from the inner end of the of the idling screw is not altered by the incorporation of the present invention thereon.

The idling screw 124 has an enlarged cylindrical head 128 having a centrally disposed annular groove 130 formed therein. The screw 124 is integral with one end of the head 128 and integral with the other end thereof is a projecting stud 132 which has a frusto-conical portion 134 having the minor diameter adjacent the head 128 and having the major diameter spaced therefrom. The outer end portion of the stud 132 is beveled as at 136 so that the end convolutions of lan electrical resistance element 138 may be snapped thereover. The electrical resistance heating element 138 is of the coil wire type and the oonvolutions have an internal diameter less than the diameter of the stud 132 but due to their resilient nature, the end convolutions may be snapped over the stud 132 as illustrated in FIGURE 2 and thus will form a positive me chanical and electrical connection between the head 128 and the electrical heating wire resistance element 138.

Enclosing the hea-ting element 138 is a sleeve of insulating material 140 which is tubular and perferably cylindrical. Enclosing the insulating sleeve 140 is a rigid metallic housing 142 also of cylindrical configuration which telescopes over the head 128 and has an inwardly crimped bead 144 formed therein for securing the housing 142 to the head 128. The insulating sleeve 140 terminates against .the outer surface of the head 138 while the end of the housing 142 is flush With the inner edge of the head 128 so that the idling metering screw 124 and the housing 142 become, in effect, a unitary integral structure.

At the outer end of the housing 142, there is provided a cylindrical plug 146 having an annular groove 148 formed therein. The head 146 is telescopically received within the housing 142 and within the end of the insulating sleeve 140 which terminates flush with the end of the housing 142. An annular bead is crimped into the groove 148 thereby securing the plug 146 in place. The end of the plug 146 disposed interiorly of the housing 142 is provided with a projecting stud 152 identical in construction to the stud 132 and the stud 152 receives the end convolutions of the heating element 138 thereby providing a secure electrical and mechanical connection between the plug or head 146 and the heating element 138. The housing 142 terminates flush with the plug or head 146 and a projecting pin 154 is integral with the outer surface of the head 146. The end of the pin 154 is tapered as at 156 and an annular groove 158 is provided intermediate the length thereof. This is a conventional snap-on type of electrical connection normally employed in automotive ignition systems or in the electrical system of an automotive vehicle. Attached to the pin `154 is a resilient split tubular connector 160 connected to an electrical conductor 162 having suitable insulation thereon. The conductor 162 has a bifurcated connector 164 at the free end thereof and intermediate the length of the conductor 162 there is provided a fuse assembly 166 of conventional construction which is in the form of an insulated housing and a fuse disposed therein. The connector 164 is connected to a suitable source of electrical potential such as the vehicle battery through a suitable switch such as the ignition switch so that the electrical heating element 138 may be energized when the ignition switch is on or an independent switch may be provided for the heating element if desired.

As the liquid fuel passes through the passage 120 and enters the orifice 118, the small portion of fuel that meters through the idling orifice will be accelerated due to the increased temperature thereof. The accelerated fuel is indicated in FIGURE l by the solid particles 168 while the unheated and unaccelerated particles are designated by the numeral 170 and are hollow or circular elements. This schematic representation of the small portion of fuel which is heated illustrates the manner in which the accelerated heated fuel will not only raise the temperature sufficient to prevent icing but also causes vaporization of the main body of fuel in such a manner that it does not overheat the main body or volume of fuel passing through the carburetor thereby eliminating any reduction in the volumetric efficiency of the carburetor since the small portion of heated fuel will have very little effect on the volumetric characteristics of the main body of fuel passing through the carburetor. Also, the heating of the idling fuel enables starting of the engine without operation of the choke valve and a smoothly idling engine is immediately obtained. The snap-on connection provided by the pin 154 enables the entire assembly to be rotated with the conductor 162 disconnected thereby enabling initial adjustment of the idling screw 124 in a conventional manner after which the electrical connection may be made by snapping on the tubular sleeve 160.

FIGURE 4 illustrates a slightly modified form of the invention in which the end plug 128 is provided with an annular rib 172 rather than a groove and the housing 142 is crimped over the rib or bead 172 by virtue of an outwardly projecting bead 174. In this construction, the end convolutions of the heating wire may be disposed between the plug 128 and the housing 142 thereby providing for a positive mechanical and electrical connection. This structure provides for a compact arrangement which may be employed for larger diameter idling adjustment screws. Referring now more specifically to FIGURES 6-8 of the drawings the numeral 10 generally designates a conventional carburetor which is shown mounted upon a mounting ange 12 of an intake manifold generally referred to by the reference numeral 14. It is to be noted that the intake manifold 14 represents any intake manifold or the like. The carburetor 10 is provided with a conventional throttle shaft 16 and butterfly valve 18 which is fixedly secured to the throttle shaft 16 for rotation therewith. A fuel passage 20 is formed in the carburetor .5 1l) for admitting metered `quantities of fuel into the intake passage 22 when the throttle valve or butterfly valve 18 is in the closed position illustratedr in FIGURE 6 of the drawings representing its setting when the internal combustion enginer (not shown) of which the intake manifold 14 comprises a part in idling. A fuel metering screw 24 having a tapered needle 25 on the inner end thereof is threadedly engaged with the carburetor and is movable axially of the passage for throttling the latter. The fuel metering screw 24 is properly adjusted to meter the iiow of fuel through the passage 20 in order to achieve the most eiiicient operation of the internal combustion engine (not shown) when the latter is idling.

The heating device illustrated in FIGURES 6-8 is generally designated by the reference numeral 26 and includes a generally elongated cylindrical housing 28 which is hollow and open at opposite ends. The housing 28 is constructed of a material which will readily conduct heat and electricity and has an abutment member generally referred to by the reference numeral 30 disposed in the housing 28 at spaced distances from one end thereof. The abutment member 30 may be secured within the housing 28 in any convenient manner such as by a press fit. The end of the housing V28 remote from the abutment member 30 has a grommet 32 frictionally secured therein and it will be noted that the grommet 32 is constructed of insulating material. The abutment member 30 has a pair of positioning lugs 34 extending from the face thereof opposing the insulation grommet 32 and one end of a terminal pin is disposed through the bore 38 formed in the grommet and is provided with a diametrically enlarged head 39. Heating means in the form of a coiled resistor 40-is disposed between the head 39 and the abutment member 30. The opposite ends of the heating element or resistor element 40 are secured to the head 39 of the terminal pin 36 and the abutment member 30 in any conventional manner such as by soldering.

One end of a conductor 42 is secured to the terminal pin 36 in any convenient manner such as by soldering and the conductor 42 may have a switch 44 disposed therein. The end of the conductor 42 remote from the terminal pin 36 may be connected to any suitable source of electrical potential. The electrical resistor element 40 is grounded by means of the housing 28 as will hereinafter become apparent.

The housing 28 has a plurality of slots 46 formed in the end thereof remote from the grommet 42 which define a plurality of axially extending fingers 48. It is to be noted that the housing 28 constructed of resilient material and that the ngers 48 frictionally grip the diametrically enlarged head 50 on the outer exposed end of the metering screw 24.

In operation, the switch 44 may be closed whereupon the flow of current though the resistor element 40 will cause the latter to become heated. The resultant heat will in turn heat the housing 28 and the abutment member 30. It will be noted that the abutment 30 is in surface-to-surface contacting relation with the free or outer end of the head 50 and that the internal surfaces of the fingers 48 are in surface-to-surface frictional engagement with the periphery of the head portion 50. Accordingly, heat is transferred from the heating device 26 by conduction to the metering screw 24 which will in turn heat the fuel passing through the passage 20. By heating the fuel passing through the passage, this fuel is accelerated into the air passage 22 thereby resulting in more efiicient operation of the internal combustion engine (not shown).

The housing 28 is enclosed by an insulated jacket generally referred to by the reference numeral 52 and it will be noted that the jacket 52 extends beyond opposite ends of the housing 28 and beyond the free end of the terminal pin 36. The jacket 52 is a non-conductor of electricity and also affords insulation about the housing 28 against heat loss.

In FIGURE 5, there is illustrated another slightly modified form of the invention and in this form, the valve body is designated by numeral 176, the housing designated by numeral 178 and the plug designated by numeral 180. The resistance heating element 182 is telescoped over a portion of the plug 180 and the insulating sleeve 184 also is telescoped over the plug 180 and the housing 178 is crimped around the plug 180 as at 186. The plug 180 includes a peripheral groove 188 with the portion of the plug 180 disposed inwardly of the housing 178 from the groove being slightly smaller in configuration as compared with the portion of the plug 180 disposed outwardly of the housing 178 in relation to the groove 188. Thus, the crimping operation as at 186 will securely retain the end convolutions of the resistance heating element 182 and also the insulation sleeve 184 and the housing 178 securely and fixedly attached to the plug 180.

In actual tests, the idling screw heating device of the present invention has substantially completely eliminated the problem of carburetor icing which begins to occur at approximately 55 degrees F., especially when the humidity is relatively high. The icing normally occurs in the volume control metering oritice and this problem is eliminated by the accelerated heated idling fuel. This results in a smoothly idling engine and reduces power loss while increaing the mileage obtained from a given quantity of gasoline. Also, choking or stalling of the vehicle is avoided and the necessity of restricting the air intake by using a choke is also substantially eliminated. This results in elimination of overrich liquid mixture in the combustion chamber since the fuel is thoroughly vaporized.

The heating device of the present invention is a permanent installation which replaces the idling adjusting screw and the source of electrical energy may be any suitable source available.

The heating effect commences with starting of the vehicle if it is connected to the voltage regulator so that the generator output supplies the electrical energy. The heating unit will heat rapidly and attain maximum output in several minutes. The heating unit then stabilizes and produces approximately 25 watts constant heating. It has been found that at an ambient temperature of 25 degrees C., the body or housing of the heater, which is preferably made of aluminum, will be approximately degrees C. and the brass tip of the screw inside of the carburetor will be at approximate-ly 75 degrees C. Thus, instead of carburetor icing being a threat beginning at approximately 13 degrees C. outside temperature, the addition of heat to the idling fuel by the heating device will provide smooth operation with no danger of icing until the temperature drops to minus 40 degrees C.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A fuel metering screw heating device comprising a housing, a metering screw having an exposed portion defining a free end face and an extending end, a heating means in said housing, said housing including means engaging the exposed portion of said metering screw in surface to surface contacting relation with the free end face of said exposed portion, said housing being elongated and provided with one open end portion snugly receiving the extending end of said fuel metering screw, said one end portion including means clampingly engaging said extended end of said screw, said clamping means including a plurality of longitudinally extending laterally spaced and resilient lingers on said one end portion disposed about the open end of said housing and frictionally embracing said extending end of the metering screw, said heating means including a heating element extending longitudinally of said housing, said heating element including an abutment member attached thereto, means securing said abutment member in said housing a spaced distance from said one end of said housing, said abutment member including a face adjacent said one end of said housing abutting the free end face of said exposed portion of said metering screw.

2. The combination of claim 1 wherein said heating element includes an elongated electrical resistor element, said abutment member comprising a contact between one end of said heating element and one end of said housing, and means insulating the other end of said heating element Ifrom the other end of said housing, the other end of said heating element projecting outwardly of the other end of said housing and adapted to be connected with a source of electrical energy.

3. The combination of claim 2 including an outer housing of insulative material enclosing said rst mentioned housing and projecting beyond the ends of said first mentioned housing.

4. An idling metering screw assembly for the carburetor of an internal combustion engine comprising; an imperforate screw having a tapered end portion and other end portion, means mounting said screw for rotatable adjustment, an electrical resistance heating element in the form of a wire coil xedly connected to the other end portion of said screw, connecting means xedly connected to said heating element at a spaced distance from the screw, said connecting means including an axial projection having an annular groove and means defining a connection for frictionally engaging the annular groove, a housing enclosing the heating element and iixedly anchored to the screw and connecting means, said housing being elongated and tubular in conguration, an insulating sleeve interposed between said heating coil and said housing, said housing having ends, said screw and said connecting means each including an end plug telescopically received in the ends of said housing, cooperating crimped means interconnecting the end plugs and housing and said heating coil having end convolutions whereby electrical energy may pass through the heating element for heating the heating element and screw and thereby heat idling fuel passing over the tapered end portion of the screw. v

5. The assembly as dened in claim 4 wherein each end plug is provided with an inwardly extending axial projection telescopically received in and secured to the end convol-utions of the heating coil.

6. The assembly as dened in claim 4 wherein one end plug is telescopically received in the end of the heating coil, one of said crimped areas also retaining the end convolutions of one end of the coil on said one plug.

References Cited by the Examiner UNITED STATES PATENTS 1,135,195 4/15 Krause 123-122 1,382,519 6/21 LePage 219-207 1,606,500 11/26 Bodman 137-341 1,663,804 3/28 Mackie 261-142 1,973,271 9/34 Smith 338-331 2,576,401 11/51 Kimmell 261--142 2,844,694 7/58 Lefebvre 338-267 2,846,989 8/58 Eskew 123-122 FOREIGN PATENTS 766,731 4/34 France. 568,565 11/57 Italy.

HARRY B. THORNTON, Primary Examiner.

RONALD R. WEAVER, Examiner. 

1. A FUEL METERING SCREW HEATING DEVICE COMPRISING A HOUSING, A METERING SCREW HAVING AN EXPOSED PORTION DEFINING A FREE END FACE AND AN EXTENDING END, A HEATING MEANS IN SAID HOUSING, SAID HOUSING INCLUDING MEANS ENGAGING THE EXPOSED PORTION OF SAID METERING SCREW IN SURFACE TO SURFACE CONTACTING RELATION WITH THE FREE END FACE OF SAID EXPOSED PORTION, SAID HOUSING BEING ELONGATED AND PROVIDED WITH ONE OPEN END PORTION SNUGLY RECEIVING THE EXTENDING END OF SAID FUEL METERING SCREW, SAID ONE END PORTION INCLUDING MEANS CLAMPINGLY ENGAGING SAID EXTENDED END OF SAID SCREW, SAID CLAMPING MEANS INCLUDING A PLURALITY OF LONGITUDINALLY EXTENDING LATERALLY SPACED AND RESILIENT FINGERS ON SAID ONE END PORTION DISPOSED ABOUT THE OPEN END OF SAID HOUSING AND FRICTIONALLY EMBRACING SAID EXTENDING END OF THE METERING SCREW, SAID HEATING MEANS INCLUDING A HEATING ELEMENT EXTENDING LONGITUDINALLY OF SAID HOUSING, SAID HEATING ELEMENT INCLUDING AN ABUTMENT MEMBER ATTACHED THERETO, MEANS SECURING SAID ABUTMENT MEMBER IN SAID HOUSING A SPACED DISTANCE FROM SAID ONE END OF SAID HOUSING, SAID ABUTMENT MEMBER INCLUDING A FACE ADJACENT SAID ONE END OF SAID HOUSING ABUTTING THE FREE END FACE OF SAID EXPOSED PORTION OF SAID METERING SCREW. 